<functional>
template <class T> struct minus;
Subtraction function object class
This class defines function objects for the subtraction arithmetic operation.
Generically, function objects are instances of a class with member function operator() defined. This member function allows the object to be used with the same syntax as a regular function call, and therefore it can be used in templates instead of a pointer to a function.
minus has its operator() member defined such that it returns the result of subtracting its second argument from its first argument.
This class is derived from binary_function and is defined as:
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template <class T> struct minus : binary_function <T,T,T> {
T operator() (const T& x, const T& y) const
{return x-y;}
};
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Objects of this class can be used with some standard algorithms such as transform or accumulate.
Members
- T operator() (const T& x, const T& y)
- Member function returning x-y.
Example
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// minus example
#include <iostream>
#include <functional>
#include <numeric>
using namespace std;
int main () {
int numbers[]={10,20,30};
int result;
result = accumulate (numbers, numbers+3, 100, minus<int>() );
cout << "The result of 100-10-20-30 is " << result << ".\n";
return 0;
}
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Output:
The result of 100-10-20-30 is 40.
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See also
| plus | Addition function object class (class template) |
| multiplies | Multiplication function object class (class template) |
| divides | Division function object class (class template) |
| modulus | Modulus function object class (class template) |
| negate | Negative function object class (class template) |
| equal_to | Function object class for equality comparison (class template) |
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